Rotary drill bit



TUg.' 6,1929. W V, sElFER-r 4 1,723,381

ROTARY DH ILL BIT Filed July 25.' 1922 2 Sheets-Sheet l y Z252/ en? Aug. 6, 1929. w V. SEUL-ERT 1,723,381

ROTARY DR ILL BI T Filed July 25. 1922 2 Sheets-Sheet 2 Patented Aug. 6, 1929.

UNITED STATES VPATENT OFFICE.

WILLI V. SEIFEBT, l' DENVER, COLDBADQ ASSIGNOB, BY HESNE ASSIGNIENTS,

T0 THE UIN-mm1 ROTARY BIT OOHPANY, A CORPORATION OF COLORADO.

ROTARY DRILL BIT.

i Application llcd July $5, 1928. Serial No. 577,302.

The object of this invention is to provide a bit for rotar drills which shall be com aratively simple, ghly efficient, and wherein the wearing parts may be readily replaced at low cost.

The invention resides in a bit body of polygonal cross sectionwhereby a plurality of flat faces are provided for the mounting of cutting discs. These cutting discs are set at angles to the axis of the bit for insuring clearance of the same from the walls of the hole, and preferably said discs are of special y construction for rapid cutting and for rapid clearing of the cuttings from the discs themselves. ytiaid discs are removably mounted upon rotatable mountings for ready replacement. The bit body also has a gradual taper longitudinally thereof so that the saine adually descends in the hole as the same is cut whereby the edges of the bit body serve to maintain the walls of the hole and prevent pebbles, rocks or earth from falling directly upon the discs. Thus the discs are left free for maximum efficiency. The lower end of the bit body receives renewable means which constitute the point of the bit, such means being preferably in the form of rotary devices set at various angles to insure a clean and rapid cut at the bottom of the hole. In the accompanying drawings wherein certain embodiments of the invention are disclosed Fig. 1 1s a plan of one form of the bit; ,see line 11;

Fig. 2 is a side elevation thereof; see line Fig. 3 is a lower end view taken from line 3 3 o-f Fig. 2;

F 4 is a cross section taken on line 4--4 of ig. 2 and indicating the arrangement and functions of the various arts;

Fig. 5 is a vertical section s owing one-of the rotary devices 'of the point;

y Fig. 6 1s a face view in detail of one of the ini roved discs; .i

ig. 7 is an edge detail thereof from line '7-7 of Fig. 6;

Fig. 8 is a cross section through lone of the discs and its mounting;

Fi 9 is a fragmentary elevation of a inodied form of bit and point arrangement, as indicated by line 9-9 of Fig. 10;

Fig. 10 is an end view thereof taken from line 10---10V of Fig. 9;

i Fig. 11 is a view partially in end elevation and partially in section taken on line 11-11 of Fig. 12;

Fig. 12 is a view partially in elevation and partially in vertical section showing the en tire bit of the and 11;

Fig. 13 is an elevation of another form which is a composite of the other forms.

In the form of Figs. 1 and 2, the body 10 of the bit is preferably integral, the lower or principal portion thereof having a plurality-of flat faces 12 which taper as they ex tend downward so that the bit tapers downward as a Whole. Preferably the upper por tion of the bit tapers upward, and has a plurality of fiat faces 112 corresponding in number to the faces 12. Thus the bit is polygonal in cross section, and the flat faces are for the purposes of receiving cutting discs 25. The body has at the edges between its faces, longitudinal beads 14 provided for the purpose of preventing rocks dislodged in the operation of the tool, from falling in from the wall of the excavation uppln the sharpened edges of the cutting disks w 'ch are mounted u on the faces of the body between the beads with their cutting edges contiguous to a circle exceeding in diameter that of the beads in the saine cross sectional plane to a determinate cutting depth of the disks.

The lower'end of the body 10 is squared oil perpendicular to the axis of the bit to provide a downwardl extending face, and from this face a plurality of rotary cutting stems 15 pro'ect at various angles to the axis of the b't. Freferably the exposed extremities of the stems or spindles 15 are upset slightly at 16 to form integral cutting discs. As the amount of upset is slight, these stems are somewhat in the natureof drills and permit the entire bit to fall after having been elevated as by riding up over a rock, without maaterial damage to the extremities thereof. The inner ends cf the stems or spindles 15 are provided with enlarged heads 18 whereby said spindles are retained within cavities in the end of bit body 10 through the medium of bushings 21 pressed into said cavities and in which bushin an intermediate portion 20 of each of the spindles is 'ournaled The center of the bit dy 10 is provided with water' passages 22, and at the upper end general form of Figs. 9, 10

i v l i the body is threaded for receiving the lower end of the drivin element 60 (Fig. 12) The discs .25 mounted upon the iiat faces 12 are of various sizes in the forni of Fig. 2 and increase in size as the width of the respective face increases. These discs are removably mounted upon rotary spindles 26 by means of threads at 27. The inner ends 126 of the spindles 26 are enlarged as shown and work upon bushings 28, while the smaller portions work upon retaining bushings 30 threaded into the cavities 29 in which die spindles are received and in which they rotate. The discs 25 may be provided with openings 32 for receiving a removing tool, and each spindle 26 is provided with a squared opening 34 which serves the double purpose of receiving a square tool when removingvor attaching a disc and of receiving oil or grease which reaches the bottom ofthe bore or cavity 29 through a small passage 36, a cork or plug 35 being provided to protect the oil or grease and to move inward against the pressure without for the purpose of positively feeding the oil or grease inward.

Preferably each disc 25 is notched transi versely at to provide peripheral. teeth 42 whose transverse edges 44 are suiciently sharp to form cutting edges. From the bases of the teeth tapering clearing cuts or notches 38 are provided on one side of the disc, the far l corner of the notch 38 extending in some instances at least, to the opposite side of the base bf the respective tooth as indicated at 46. Thus at each point 46a further cutting portion is provided by the sharp corner. The side of the disc opposite the tapering notches or grooves 38 is beveled as seen at 48, this side bein disposed opposite the face of' the body l 10o the bit. The axes of the spindles o the I are positioned adjacent or within the path of '.said edges or beads.

In the general form of Figs. 9, 10, 11 and 12, the polygonal cross section of the bit body y at all points is retained and dat faces are provided for mounting the discs 25 thereon. But

' instead of havingfthe faces continuous and producin the taper of the bit body by tapersaid aces, the taper is produced by provi ing a plurality o sections of gradually i changing sizes, and preferably the number of sizes upon these sections varies, the nurnber increasing 'as the diameter of the section increases. In this manner a greaternumber of discs may be placed upon the sides of the body and the discs 25 may be all of the same size or approximately so.

Thus for the lower end of the bit, a square section 50 may be used upon whose flat faces the discs 25 are mounted as in the other forni. Next above this a pentagonal section 52 may be employed, and as shown -this section may have two zones o different width. Also it may be convenient when the height of the individual sections is not great, to have a secl ond pentagonal section 152 also having two zones of different width or diameter. In

practice, the lower edges of each section and zone will be wiped oliE or beveled as indicated at 54 to form beveled faces which cause one zone or section to taper somewhat more gradually into the adjacent one. Above the pentagonal sections, a hexagonal section 55 having two zones may be employed, and next above an octagonal section 56 having two zones. A cap 58 whose upper faces taper upwardly toward the center may be used, corre sponding with the upwardly tapering faces 112 of the forni of Fig. 2Q The driving element 60 will have connection with thevupper section, and the various sections will be removably connected in order that a sectional bit of any desired size or form may be built up. v

Upon the lower end of the lowermost section of this form, discs like the discs 25 areused instead of the cutting stems 15. These discs are arranged in two pairs 125 and 225 disposed at diagonally opposite corners, all discs being set at an angle to the axis of the 'bit and one pair being set at a greater angle than the other. The inner edges of these discs are the trailing edges and theend of the section 50 is cut out as indicated at 150 to receive such inner portions, said inner portions thus being partially embeddedvin the section 50.

Fig. 13 shows a form of bit com. osed of a plurality ofsections which are po ygonal in form and have various numbers of sides as in the form of Fig. 12. zThe faces of each section taper however, so that it is not necessary to cut or wipe offthe lower edges to pro-` duce a more or less uniform' taper of the bit body asa whole., Here we have a square lower end 50 like that of Fig. 12 provided with the cutting stems 15 of Figs. 2 and 5. Above this in order comes a tapered section 62 which is square in cross section, a tapered pentagonal section 64, a tapered hexagonal section 65, a tapered octagonal section 66, and an upwardly tapered octagonal section 68 to fit section' 66. The upper sections are provided with beads 14, but the square sections do not re uire beads 2o perform the 'wall retaining unction since their corners project far enough.

In the operation of the device, the bits will be rotated as indicated by arrows with the `result that the cutting stems or the discs 125 or 225 on the lower end of the respective bit will cut out the bottom of .the hole. As the bit rotates and descends the spiral path of each of the discs will cause the sides of the hole' to be gradually cut away until the desired diameter is obtained. The number of discs 25, 125, 225 and of the stems 15 will be such as to perform the Work eiciently. The inclination of all the discs and of the stems 15 will be such as to cause rotation of the various parts individually as the bit body is rotated. The passage of water down through the water channels 22 causes the dbris to be Washed upward around the bit and to the top of the hole. When the hole cannot be drilled readily the stems 15 wil-l preferably be employed at the lower end of the bit since they will better resist the shock 20 when the bit rides up over rocks and drops after assing vover them. The form of cutting dlsc shown in Figs. 6, 7 and 8 will clear itself as the work progresses and at the same time eiicient cutting edges are presented. When a disc wears outa new one is substi tuted -upon the res ectivespindle 26. Lubrication is .insure by pressure upon the cork or plug 35 in the outer end ofeach lubricant carrying opening 34.

The upwardly beveled faces 112, 58 and 68 which carry discs 25 are provided for the pur.-

posesof assisting the bit in drilling its way.

upward vin the event of a cave-in.

I claim: p p

1. A rotary drill bit comprising ar tapering body of polygonal section, having beads at the edges between its faces, and cutting members on said faces having their cutting edges contiguous to aj circle exceeding in diameter that of the beads in the same cross sectional plane to a determinate cutting depth of the members.

2. A rotary drill bit comprising a tapering body having a plurality of faces arranged .in series-superposed one Vabove another, and

cutting members on said faces, the number I of faces in the series varying in ratio to the same.

4.`A rotarylldrill bit comprising a bodyA havinglongitudinal beads at equal distances from itsy axis and cutting members on the body between said beads, having their cutting edges. in a circle slightly exceeding that of the beads in the same cross-sectional plane to a determinate cutting depth of 'the members.

5. A bit for deep well drilli through earth and rock comprising in com ination a bit body rotatable about a vertical axis, a plurality of exteriorly located rotatable cutters arranged to engage the material to be cut at angles substantially less than 90, whereby to loosen the material with a cutting Wedging action, and being arranged at diii'erent distances from the axis of the bit to cut a plurality of paths of different diameters, there being agreater number of cutters provided to cut the paths of greater diameter than are provided to cut the paths of smaller diameter, whereby the cutting wear on the respective cutters is practically uniforml distributed.

6. A bit for deep well drilin through earth and rock comprising in com ination a bit body rotatable about a vertical axis, a plurality of exteriorly located rotatable cutters of frusto-conical shape mounted on shafts carried in holes in the bit body, the cutting edges of said cutters being provided/by the conjunction of the conical surface ofthe cutter with its flat end face,said cutters being arranged to engage the material to be cut at ani gles substantie loosen the material with a cutting wedging action, and being mounted at different distances' from the axis of the bit whereby to cut a so that the cutting wear on one cutter will not be greatly disproportionate to the wear on other cutters.

7. bit for deep well drilling through earth and rock comprising in combination a bit body rotatable about av vertical axis, plurality of exteriorly-'located rotatablecutters of frusto-conicai shape mounted on shafts4 carried'in holes in the .bit body, the cutting edges of said cutters being provided by the conjunction of the conical surface of the cutter with its fiat end face, said cutters being arranged to engage the material to be cut at angles substantially less than 900, whereby to loosen the material with a cutting wedging action, and being mounted on said bit body at different elevations and different distances from'the axis of the bit, whereby to cut a pluly less than 90, whereby to rality of paths of increasing diameter, said A,

cutters being distributed on said bit body so that the cutting. wear on one cutter will. not be greatly disproportionate to the wear yon other cutters.

In testimony whereof I alx my signature.

WILLIAM V. SEIFERT. 

